package array;

import java.util.Arrays;

public class PairSum
{

  // given an array, check the index of two number that sum up with a certain
  // number
  public static void pairSum(int[] array, int sum)
  {
    if (array == null || array.length == 0) return;
    Arrays.sort(array);
    for (int i = 0, j = array.length - 1 ; i <= j ; i++, j--) {
      if (array[i] + array[j] == sum) {
        System.out.println("there is a pair " + array[i] + " " + array[j]);
        i++;
        j--;
      }
      else if (array[i] + array[j] > sum) {
        j--;
      }
      else
        i++;
    }
  }

  /**
   * @param args
   */
  public static void main(String[] args)
  {
    // TODO Auto-generated method stub
    int test[] = { 9, 3, 6, 5, 7, -1, 13, 14, -2, 12, 0 };
    pairSum(test, 12);
  }

}
